Geochemical detection of carbon dioxide in dilute aquifers

<p>Abstract</p> <p>Background</p> <p>Carbon storage in deep saline reservoirs has the potential to lower the amount of CO₂emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO₂gas leak into dilute groundwater are important measures for the potential release of CO₂to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO₂storage reservoir. Specifically, we address the relationships between CO₂flux, groundwater flow, detection time and distance. The CO₂flux ranges from 10³to 2 × 10⁶t/yr (0.63 to 1250 t/m²/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.</p> <p>Results</p> <p>For the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO₂into an overlying aquifer because elevated CO₂yields a more acid pH than the ambient groundwater. CO₂leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO₂buoyancy. pH breakthrough curves demonstrate that CO₂leaks can be easily detected for CO₂flux ≥ 10⁴t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO₂dissolves in the aqueous phase in the lower most permeable unit and does not reach the monitoring well. Sustained pumping in a developed aquifer mixes the CO₂-affected water with the ambient water and enhances pH signal for small leaks (10³t/yr) and reduces pH signal for larger leaks (≥ 10⁴t/yr).</p> <p>Conclusion</p> <p>The ability to detect CO₂leakage from a storage reservoir to overlying dilute groundwater is dependent on CO₂solubility, leak flux, CO₂buoyancy, and groundwater flow. Our simulations show that the most likely places to detect CO₂are at the base of the confining layer near the water table where CO₂gas accumulates and is transported laterally in all directions, and downstream of the vertical gas trace where groundwater flow is great enough to transport dissolved CO₂laterally. Our simulations show that CO₂may not rise high enough in the aquifer to be detected because aqueous solubility and lateral groundwater transport within the lower aquifer unit exceeds gas pressure build-up and buoyancy needed to drive the CO₂gas upwards.</p

ANALISIS KETERSEDIAAN TANAH DI KAWASAN PARIWISATA LIKUPANG

This study aims to analyze the location of land availability and the direction of land availability from the aspect of Spatial Designation Plans and land issues. The research was carried out from November 2021 to January 2022 which is located in the Likupang tourism area. The method used in this research is Overlay Analysis with GIS software and descriptive analysis obtained through Indepth Interview. The data used are primary data and secondary data. The results of the research analysis obtained that the availability of land at the location was classified into available and unavailable. The area of available land is 829.47 Ha (17.97%) while the area of land that is not available is 3,716.55 Ha (80.54%). The available land locations consist of available non-agricultural cultivation covering an area of 664.86 Ha (14.41%) and agricultural cultivation covering an area of 164.61 Ha (3.57%). The location of land that is not available is limited to protected activities covering an area of 1,030.06 Ha (22.32%), optimal use of non-agricultural land of 217.33 Ha (4.71 %), optimal use of agricultural land covering an area of 2,145.78 Ha ( 46.5%) and land use adjustment of 323.38 Ha (7.01%). The direction of land availability, namely the location of the available land is directed based on the allotment of space so that it is obtained for investment activities covering an area of 664.86 hectares and commodity activities covering an area of 164.61 hectares. At the location of the available land, there is a potential land dispute of 2 hectares. So that the availability of clean and clear land (no dispute) is&nbsp;(827.47%)

TRICHOTHIODYSTROPHY WITHOUT PHOTOSENSITIVITY - BIOCHEMICAL, ULTRASTRUCTURAL AND DNA-REPAIR STUDIES

A case of trichothiodystrophy (TTD) without photosensitivity is reported in an 8-year-old girl. Electron microscopic (EM) examination of the keratinocytes showed fibrillary bundles in the cytoplasm thinner and less electron dense than those of the normal cells and large membrane-bound vacuoles filled with granular-filamentous material. These findings could indicate a disturbance in the protein metabolism in tissues of ectodermal origin, explaining also the functional abnormalities of the central nervous system in TTD patients. The results of cellular DNA repair studies after UV irradiation in cultured fibroblasts showed normal levels of unscheduled DNA synthesis. This finding indicates that UV hypersensitivity is not constantly present in TTD

A global database of ant species abundances

What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51 ,388 ant abundance and occurrence records of more than 2,693 species and 7,953 morphospecies from local assemblages collected at 4,212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type, and degree of disturbance. The aim of compiling this data set was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardized methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing data set